Carburetor

ABSTRACT

This invention involves a time delay in the opening of the power valve to cut out some or all of the power valve operation for city driving and still allow the power valve to come in for continued high power operation at power normally requiring a power valve enrichment to keep from over-heating the engine and valves at such continued high power. Such a power valve cut out for city driving with lower peak combustion temperatures for lower NOx (nitrous oxides) on city driving and lower temperatures of the exhaust valves, etc. over those temperatures that would exist if no power enrichment were used on continued high power operation. The method of timing the delay in power valve come in is by the use of a reservoir between the intake suction and the power valve piston with a check valve to hold suction in the reservoir and a very limited bleed down for delayed reduction of suction to operate the power valve.

United States Patent Walker 51 May 23,1972

[541 CARBURETOR Brooks Walker, 1280 Columbus Avenue, San Francisco,Calif. 94133 [22] Filed: Feb. 24, 1970 [21] Appl.N0.: 13,550

[72] Inventor:

[56] References Cited UNITED STATES PATENTS 3,366,194 l/l968 Walker etal ..l23/l27 X Primary ExaminerWendell E. Burns ABSTRACT This inventioninvolves a time delay in the opening of the power valve to cut out someor all of the power valve operation for city driving and still allow thepower valve to come in for continued high power operation at powernormally requiring a power valve enrichment to keep from over-heatingthe engine and valves at such continued high power. Such a power valvecut out for city driving with lower peak combustion temperatures forlower NO (nitrous oxides) on city driving and lower temperatures of theexhaust valves, etc. over those temperatures that would exist if nopower enrichment were used on continued high power operation. The methodof timing the delay in power valve come in is by the use of a reservoirbetween the intake suction and the power valve piston with a check valveto hold suction in the reservoir and a very limited bleed down fordelayed reduction of suction to operate the power valve.

12 Claims, 2 Drawing Figures PATENTED MAY 2 3 I972 INVENTOR. BROOKSWALKER CARBURETOR An object of the invention is as stated in the aboveabstract.

Another object is the use of a reservoir to temporarily hold a suctionlevel prevailing in the intake before the sustained power operation atsuctions when power valve enrichment is needed to hold exhaust valvetemperatures within safe temperature limits. A limited bleed to theintake manifold forms the delay period so that the delayed lower suctionin the reservoir (that is, connected to the power valve operating pistonor movable wall) will act as a delayed timer in the power valve come onoperation. Such a delay in power valve come on will result in no powervalve operation in some or all city driving. A fast get away from atraffic light would be over before the timer would turn on the powervalve. Also, as in San Francisco, most hills are only one or two blockslong and on .such a hill the leaner mixture without power valveoperation will not result in excessive exhaust valve temperatures duringsuch hill climbing, with the leaner mixtures needed for low HC emissionsrequired for smog control. Continued power valve operation at below 7 to10 inches intake suction (i.e. l- 0 inch Hg) would bring in the powervalve, as in going over the Donner Summit, involving 20 or more miles ofcontinuous grades to 7,000 elevation at 60 70 mph at suctions 5 0 inchHg where such operation at a lean mixture might cause engine or valveoverheating and higher emissions might be permissible. The fuel mixtureshould be maintained so as not to cause too lean a mixture, causingstumble and missing with sudden full power operation and all citydriving should result in exhaust emissions within the prescribed limitsbut higher limits might be acceptable on continued mountain climbing outof the city basins, such as Los Angeles, San Jose, etc.

Another object is to provide a timer that does not require electricalcircuits near the carburetor or a clock timer but to have such a timeras a part of a carburetor assembly and preferably under the umbrella orbelow of the air cleaner.

It is well known that exhaust HC emissions are higher when operating onthe power valve than when not, and this invention is to automaticallyefiectively cut out power valve operation for most or all normal citydriving but still allow power valve enrichment to hold enginetemperatures within normal power valve operating limits on continuedoperation when such enrichment is needed outside city basins.

With some power valve enrichment nitrous oxides are reduced as the peaktemperatures of combustion are lower with richer mixtures and a twostage power valve may be desirable wherein some enrichment is providedby a limited stroke operating somewhat below inches Hg suction, maybe 710inches, and the delay suction for full power valve operation beingdelayed due to the slow equalizing of suction in the reservoir and thelower suction in the intake manifold.

My invention Exterior Control of Power Valve of a Carburetor", US. Pat.No. 3,301,540, dated Jan. 31, 1967, covers a manual control of a powervalve operation and a tapered power valve so any portion of the powervalve flow can be manually controlled, i.e. cut out all or part for citydriving and cut in for mountain climbing out of the actual area. Thisinvention makes such manual control automatic and may not require anexterior signal, though it could be used if desired by legislation.

I have illustrated my invention by way of example in the accompanyingdrawings, in which:

FIG. 1 is a side elevation of an engine and foot throttle control as ona vehicle employing one form of the invention.

FIG. 2 is an enlarged side elevation view shown in larger scale of thecarburetor, shown in FIG. 1, with portions cut away.

In both figures like numerals of reference refer to corresponding parts.

In FIGS. 1 and 2 l have shown a carburetor 10 mounted on engine 9attached to intake manifold 8 with intake ports 7 leading to the enginecylinder. Exhaust manifold 6 is connected to exhaust pipe 5 and theusual muffler and tail pipe, not shown.

An air cleaner 13 is mounted on top of the carburetor. A choke valve 12is provided upstream of the venturi 11 where fuel is admitted throughschematic tube 14a from float bowl 14. Throttle blade 15 is mounted onshaft 16 and controlled by arm 17. Ann 17 is connected to foot throttle20 by rod 18 and bell crank 220 with curved sections 22 approximately ona radius about pivot 23 to pass through a hole 25 in firewall 26 of avehicle; extension crank 22a is attached to control rod 18 at pivot 22b.Roller 21 reduces friction on sliding contact with foot pedal 20 in aconventional manner. Fuel under pressure enters the carburetor by line45, past float valve 44, operated by float 41 and support arm which ispivoted at 42 to bracket 43.

Power valve 60 has a tapered upper portion and a ring portion 60a. Aspring 61 urges the power valve ring 60a against seat 63 surroundingpower valve orifice 64. Spring 61 seats against guide plug 65. Fuelenters the main jet passage 14a and from opening 64 past seat 60athrough passage 62 from the fuel in the main float bowl past power valve60. Main fuel for jet passage 14a may be admitted by main jet intakeorifice 14b leading to passage 14a in a conventional manner for somecommercial carburetors. A power valve operating cylinder 50 supports apiston plunger 52 which limits the upper stroke, and is attached to acup or seal 51. A piston rod 53 is attached to cup 51 and has a head530. A spring 54 urges cup 51 downward and may be so tensioned alongwith the tension (in compression) of spring 61 which urges power valve60 to the closed position that the power valve 60 will only open after adelay and continued operation of the engine at intake suctions for morepower than at 10 or 8 inches Hg suction. When the suction on cup 51 isbelow a desired limitspring 53 overcomes 7 spring 61 and opens fuel flowpast valve 60. The delay in opening valve 60 is accompanied by insertinga reservoir 32 between the engine side of butterfly throttle 15 and thepower valve operating cylinder 50 by tube 36 to check valve 33, with aslow bleed down valve 35 in bypass line 34 from reservoir 32 back to theintake 8. Tube 31 connects reservoir 32 to power valve operatingcylinder 50.

In operation, when idling or cruising at 17 to 12 inches Hg suction,piston and cup 51 are held up by such suction acting against spring 53and no power valve fuel flows. Acceleration is accomplished without fullpower valve enrichment for a short distance as in city driving. The dropin suction in reservoir 32 will be slow through needle valve 35 so thepower valve will not open by allowing piston and seal 51 to be pusheddown by spring 54 to open power valve 60 against closing spring 61. Thepower valve will open on continued full power operation for over 10seconds or longer wide open operation, as in climbing from the bosAngeles Basin over the mountains to Las Vegas or from Colfax to theDonner Summit of about 7,000. The shape and taper of the power valve 60may allow some power valve operation at suction below full power toallow a correct mixture for low HC and NO (nitrous oxides) at some wideopen city driving but not full power valve flow on nearly all citydriving operation.

The limits of suction mentioned where the power valve opens are examplesonly applicable to some engines and the suction where the power valveopens may vary on other engmes.

Other features may be pointed out in the accompany claims.

I have illustrated my inventions in these various forms; however, manyother variations may be possible within thescope of this invention.

To those skilled in the art to which this invention relates many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the spirit andscope of the invention. The disclosures and description herein arepurely illustrative and are not intended to be in any sense limiting.

I claim:

1. A carburetor, an engine, an intake manifold to which the carburetoris attached, said carburetor comprising a throttle valve, a power valveincluding an actuating device, a delay mechanism for delaying theopening of said power valve after operating at high suctions in theintake manifold and then suddenly operating at or near wide openthrottle with low suctions, such mechanism allowing power valve openoperation after delaying the opening of said power valve on continuedoperation at open throttle.

2. A device as defined in claim 1, said power valve being controlled bysuction from said intake manifold on the engine side of said throttlevalve, the opening of said power valve being delayed by the delaymechanism for more than 2 seconds after changing from said high intakesuction operation to wide open throttle operation of said engine.

3. A device as defined in claim 1, in which the actuating devicecomprises power means to operate said power valve, said delay mechanismcontrolling said power means for the opening of said power valve after apredetermined time following the change of operation at high suction tooperation at or near wide open throttle with low suction.

4. A device as defined in claim 3, in which the power means to open saidpower valve operates when the suction is less than 7 inches Hg intakesuction, said delay occurring after operation at idle and quicklychanging the throttle to operate at less than 7 inches Hg suction nearwide open throttle operation.

5. A device as defined in claim 4, in which such delay is more than 4seconds, said time delay mechanism involving a reservoir for suctionfrom said intake manifold, a controlled bleed valve between said intakemanifold and said reservoir, a bypass to said intake with a check valveallowing higher suction to flow from said intake to said reservoirfreely but not from said reservoir to said intake manifold, saidreservoir being connected to said actuating device to control theopening of said power valve when suction in said reservoir is less thana selected limit.

6. A device as defined in claim 1, said mechanism comprising a reservoirinserted between the intake manifold and the power valve actuator, saidreservoir being connected to said intake manifold by an unrestrictedline with a check valve therein and a greatly restricted flow line fromsaid reservoir to said intake manifold,

7. A carburetor, an engine having an intake manifold to which thecarburetor is attached, said carburetor comprising a throttle valve, apower valve and an actuating device for opening said power valve,control means for operating the actuating device in response to lowsuction in the intake manifold, said control means including a timingmechanism initiated by a sudden operation of the engine at or near wideopen throttle with low suction following operation at high suctions,said control means operating the actuating device to open the powervalve a predetermined period of time following said sudden decrease insuction, said control means being operative only on continued saidoperation of the engine at low suction at least for the predeterminedperiod of time.

8. The apparatus defined in claim 7 wherein the timing mechanismincludes a fluid reservoir connected by passageways between the intakemanifold and the actuating device for operating the power valve, therebeing a pair of passageways between the manifold and reservoir, one ofsaid pair of passageways being unrestricted to fluid flow in onedirection and provided with a check valve, and the other of said pairgreatly restricting the fluid flow.

9. The apparatus defined in claim 7 wherein the predetermined time ismore than 2 seconds.

10. The apparatus defined in claim 7 wherein the power valve is openedby the control means at suctions below 7 inches of Hg in the manifold.

11. A device as defined in claim 6 in which said greatly restricted flowline includes means accessible exteriorly of the carburetor foradjusting the amount of restriction.

12. The apparatus defined in claim 8 in which the restriction of thefluid flow in the other of said pair of passages is provided byadjustable means accessible exteriorly of the carburetor for varying theamount of restriction.

1. A carburetor, an engine, an intake manifold to which the carburetoris attached, said carburetor comprising a throttle valve, a power valveincluding an actuating device, a delay mechanism for delaying theopening of said power valve after operating at high suctions in theintake manifold and then suddenly operating at or near wide openthrottle with low suctions, such mechanism allowing power valve openoperation after delaying the opening of said power valve on continuedoperation at open throttle.
 2. A device as defined in claim 1, saidpower valve being controlled by suction from said intake manifold on theengine side of said throttle valve, the opening of said power valvebeing delayed by the delay mechanism for more than 2 seconds afterchanging from said high intake suction operation to wide open throttleoperation of said engine.
 3. A device as defined in claim 1, in whichthe actuating device comprises power means to operate said power valve,said delay mechanism controlling said power means for the opening ofsaid power valve after a predetermined time following the change ofoperation at high suction to operation at or near wide open throttlewith low suction.
 4. A device as defined in claim 3, in which the powermeans to open said power valve operates when the suction is less than 7inches Hg intake suction, said delay occurring after operation at idleand quickly changing the throttle to operate at less than 7 inches Hgsuction near wide open throttle operation.
 5. A device as defined inclaim 4, in which such delay is more than 4 seconds, said time delaymechanism involving a reservoir for suction from said intake manifold, acontrolled bleed valve between said intake manifold and said reservoir,a bypass to said intake with a check valve allowing higher suction toflow from said intake to said reservoir freely but not from saidreservoir to said intake manifold, said reservoir being connected tosaid actuating device to control the opening of said power valve whensuction in said reservoir is less than a selected limit.
 6. A device asdefined in claim 1, said mechanism comprising a reservoir insertedbetween the intake manifold and the power valve actuator, said reservoirbeing connected to said intake manifold by an unrestricted line with achecK valve therein and a greatly restricted flow line from saidreservoir to said intake manifold.
 7. A carburetor, an engine having anintake manifold to which the carburetor is attached, said carburetorcomprising a throttle valve, a power valve and an actuating device foropening said power valve, control means for operating the actuatingdevice in response to low suction in the intake manifold, said controlmeans including a timing mechanism initiated by a sudden operation ofthe engine at or near wide open throttle with low suction followingoperation at high suctions, said control means operating the actuatingdevice to open the power valve a predetermined period of time followingsaid sudden decrease in suction, said control means being operative onlyon continued said operation of the engine at low suction at least forthe predetermined period of time.
 8. The apparatus defined in claim 7wherein the timing mechanism includes a fluid reservoir connected bypassageways between the intake manifold and the actuating device foroperating the power valve, there being a pair of passageways between themanifold and reservoir, one of said pair of passageways beingunrestricted to fluid flow in one direction and provided with a checkvalve, and the other of said pair greatly restricting the fluid flow. 9.The apparatus defined in claim 7 wherein the predetermined time is morethan 2 seconds.
 10. The apparatus defined in claim 7 wherein the powervalve is opened by the control means at suctions below 7 inches of Hg inthe manifold.
 11. A device as defined in claim 6 in which said greatlyrestricted flow line includes means accessible exteriorly of thecarburetor for adjusting the amount of restriction.
 12. The apparatusdefined in claim 8 in which the restriction of the fluid flow in theother of said pair of passages is provided by adjustable meansaccessible exteriorly of the carburetor for varying the amount ofrestriction.